StdPNG.h

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/*
 * OpenClonk, http://www.openclonk.org
 *
 * Copyright (c) 2001-2009, RedWolf Design GmbH, http://www.clonk.de/
 * Copyright (c) 2013-2016, The OpenClonk Team and contributors
 *
 * Distributed under the terms of the ISC license; see accompanying file
 * "COPYING" for details.
 *
 * "Clonk" is a registered trademark of Matthes Bender, used with permission.
 * See accompanying file "TRADEMARK" for details.
 *
 * To redistribute this file separately, substitute the full license texts
 * for the above references.
 */
// png file reading functionality
 
#ifndef INC_STDPNG
#define INC_STDPNG
 
#include <png.h>
 
class CPNGFile
{
private:
    BYTE *pFile;      // loaded file in mem
    bool fpFileOwned; // whether file ptr was allocated by this class
    int iFileSize;    // size of file in mem
    int iPixSize;     // size of one pixel in image data mem
    FILE *fp;         // opened file for writing
 
    BYTE *pFilePtr;   // current pos in file
 
    bool fWriteMode;              // if set, the following png-structs are write structs
    png_structp png_ptr;          // png main struct
    png_infop info_ptr, end_info; // png file info
 
    BYTE *pImageData; // uncompressed image in memory
    int iRowSize;     // size of one row of data (equals pitch)
 
    void Read(BYTE *pData, int iLength);  // read from file
    bool DoLoad();    // perform png-file loading after file data ptr has been set
public:
    unsigned long iWdt, iHgt;                               // image size
    int iBPC, iClrType, iIntrlcType, iCmprType, iFltrType;  // image data info
public:
    CPNGFile();     // ctor
    ~CPNGFile();    // dtor
 
    void ClearPngStructs();                       // clear internal png structs (png_tr, info_ptr etc.);
    void Default();                               // zero fields
    void Clear();                                 // clear loaded file
    bool Load(BYTE *pFile, int iSize);            // load from file that is completely in mem
    DWORD GetPix(int iX, int iY);                 // get pixel value (rgba) - note that NO BOUNDS CHECKS ARE DONE due to performance reasons!
    // Use ONLY for PNG_COLOR_TYPE_RGB_ALPHA!
    uint32_t * GetRow(int iY)
    {
        return reinterpret_cast<uint32_t *>(pImageData+iY*iRowSize);
    }
    bool Create(int iWdt, int iHgt, bool fAlpha); // create empty image
    bool SetPix(int iX, int iY, DWORD dwValue);   // set pixel value
    bool Save(const char *szFilename);            // save current image to file; saving to mem is not supported because C4Group doesn't support streamed writing anyway...
 
    BYTE *GetImageData() { return pImageData; }   // return raw image data
    int GetBitsPerPixel();                        // return number of bits per pixel in raw image data
 
    static void ScheduleSaving(CPNGFile *png, const char *filename); // start a background thread to save the png file. then free the passed png.
    static void WaitForSaves(); // wait until all pending saves are finished
 
private:
    static void PNGAPI CPNGReadFn(png_structp png_ptr, png_bytep data, size_t length); // reading proc (callback)
};
#endif //INC_STDPNG